<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div class="c">xxxxx</div>
  <div class="d">111</div>
</body>
<style>
  *{
    margin: 0;
    padding: 0;
  }
  html, body{
    height: 100%;
  }
  .c{
    height: 10px;
  }
  .d{
    height: calc(90%);
    background-color: antiquewhite;
  }
</style>
</html>